The monograph covers the background, progress, and outcome of the "Castro case," a racial discrimination lawsuit filed in 1982 by a group of Chicano and Black parents and their children against the Phoenix (Arizona) Union High School District alleging that their 94% minority high school was unfairly singled out for closure due to a declining enrollment problem in the city. The report, written by an expert witness for the plaintiffs, attempts to show how social science research can be brought to bear on such a case. The conceptual framework presented concentrates on the issues of discriminatory intent and impact. Regarding intent, a detailed analysis shows how criteria for conduciveness to school closure used by the district were inherently biased against minority schools. Criteria include comparison of current course offerings, assessment of student achievement and special education and gifted needs, experience of teaching staff, number of teachers by subject area, campus adequacy to serve handicapped students, and educational adequacy. Several theoretical and empirical bases in psychological and educational literature are cited to shed light on the issue of alleged adverse impact on the displaced minority students. These effects are discussed in the context of policy implications for equal educational opportunity. Twelve pages of references conclude the report. (NEC)